Relationship Between Metacommunity Robustness To Habitat Loss And The Architecture Of Antagonistic And Mutualistic Networks

Exploring the relationship between community stability and the architecture of ecological networks has already become a fundamental issue in ecology.Recent studies have shown that the network architecture favoring stability fundamentally differs between mutualistic and antagonistic networks at a local scale,yet it remains unclear whether this view holds at the landscape scale.In particular,ongoing habitat loss,resulting from natural and anthropogenic disturbances,have already disrupted species trophic interactions,leading to severe secondary extinctions and therefore biodiversity loss.As such,we developed a patch-dynamic model based on metapopulation theory,to assess the effect of network structure on metacommunity robustness of mutualism(5760 model webs)vs.antagonism(5760 model webs)to habitat loss.For model validation,this study compared the modelling predictions with the architecture of a large collection of observed networks in nature(including 186 mutualistic and 31 antagonistic bipartite networks).Several results were obtained as follows:(1)At low levels of habitat loss,both mutualistic and antagonistic networks became more connected but less nested than their initial structures,while the modularity was almost not influenced.Yet,an increase of habitat loss tended to shape more nested and higher modular webs irrespective of mutualistic or antagonistic.(2)Increasing network connectance expectedly promoted system robustness to habitat loss,while metacommunity persistence showed contrasting responses to nestedness(negatively)and modularity(positively).Furthermore,both nestedness and modularity interacted to significantly reduce species diversity.However,increasing habitat loss strongly weakened these structural effects due to its dominant role in determining species survival.(3)The meta-analysis of both observed mutualistic and antagonistic networks shows the linear(log-log transformation)relationship between network size and connectance,and both types of network display high levels of nestedness while relatively low levels of modularity.This study found similar linking patterns(including connectance,nestedness and modularity)in both modeling and observed networks,thereby demonstrating model validity.Overall,in stark contrast to previous views at local scales,current study found the same metacommunity responses of mutualistic and antagonistic networks to habitat loss(i.e.similar architectural properties),thereby offering new theoretical support for the mechanism of biodiversity maintenance.